Extreme binge drinking-consuming 10 or 15 or more drinks in a row-has recently been recognized as a relatively prevalent and highly problematic behavior among American young people. Given that alcohol use reaches lifetime peaks in the 20s, understanding the patterns and predictors of extreme binge drinking across the transition to adulthood is particularly critical. The current application is to use existing national prospective data from Monitoring the Future (MTF) to examine the development of extreme binge drinking across young adulthood (from ages 18 to 30) in the US. Specific aims are to (1) examine how extreme binge drinking varies based on patterns of college enrollment and attainment, (2) document normative age-related changes in extreme binge drinking across young adulthood, and the extent to which they vary based on social role statuses and demographic indicators and are associated with trajectories of other substance use, and (3) investigate concurrent associations between reasons for drinking and extreme binge drinking behaviors. MTF added questions regarding extreme binge drinking for a random one-sixth of participants in 2005. Data for the current application from 2005-2013 include N~9,400 observations from N~4,000 individuals. The proposed project will identify developmental patterns and predictors of extreme binge drinking for the first time, in national samples including both college attenders and non-attenders, providing critical information for health promotion and intervention efforts targeting high-risk alcohol behaviors among young adults.